/******************************************************************
 *
 * Copyright 2018 Samsung Electronics All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 ******************************************************************/

/****************************************************************************
 *
 *   Copyright (C) 2016 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <tinyara/config.h>

#include <stdbool.h>
#include <sched.h>
#include <debug.h>

#include <tinyara/arch.h>
#include <tinyara/sched.h>
#include <arch/chip/core-isa.h>

#include "sched/sched.h"
#include "group/group.h"
#include "xtensa.h"

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_block_task
 *
 * Description:
 *   The currently executing task at the head of
 *   the ready to run list must be stopped.  Save its context
 *   and move it to the inactive list specified by task_state.
 *
 * Input Parameters:
 *   tcb: Refers to a task in the ready-to-run list (normally
 *     the task at the head of the list).  It most be
 *     stopped, its context saved and moved into one of the
 *     waiting task lists.  It it was the task at the head
 *     of the ready-to-run list, then a context to the new
 *     ready to run task must be performed.
 *   task_state: Specifies which waiting task list should be
 *     hold the blocked task TCB.
 *
 ****************************************************************************/

void up_block_task(struct tcb_s *tcb, tstate_t task_state)
{
	struct tcb_s *rtcb = this_task();
	bool switch_needed;

	/* Verify that the context switch can be performed */

	ASSERT((tcb->task_state >= FIRST_READY_TO_RUN_STATE) && (tcb->task_state <= LAST_READY_TO_RUN_STATE));

	/* Remove the tcb task from the ready-to-run list.  If we
	 * are blocking the task at the head of the task list (the
	 * most likely case), then a context switch to the next
	 * ready-to-run task is needed. In this case, it should
	 * also be true that rtcb == tcb.
	 */

	switch_needed = sched_removereadytorun(tcb);

	/* Add the task to the specified blocked task list */

	sched_addblocked(tcb, (tstate_t)task_state);

	/* If there are any pending tasks, then add them to the ready-to-run
	 * task list now
	 */

	if (g_pendingtasks.head) {
		switch_needed |= sched_mergepending();
	}

	/* Now, perform the context switch if one is needed */

	if (switch_needed) {

		/* Are we in an interrupt handler? */

		if (CURRENT_REGS) {
			/* Yes, then we have to do things differently.
			 * Just copy the CURRENT_REGS into the OLD rtcb.
			 */

			xtensa_savestate(rtcb->xcp.regs);

			/* Restore the exception context of the rtcb at the (new) head
			 * of the ready-to-run task list.
			 */

			rtcb = this_task();
#if CONFIG_RR_INTERVAL > 0
			rtcb->timeslice = MSEC2TICK(CONFIG_RR_INTERVAL);
#endif

			/* Then switch contexts.  Any necessary address environment
			 * changes will be made when the interrupt returns.
			 */

			xtensa_restorestate(rtcb->xcp.regs);
		}

		/* Copy the user C context into the TCB at the (old) head of the
		 * ready-to-run Task list. if up_saveusercontext returns a non-zero
		 * value, then this is really the previously running task restarting!
		 */

		else if (!xtensa_context_save(rtcb->xcp.regs)) {
#if XCHAL_CP_NUM > 0
			/* Save the co-processor state in in the suspended thread's co-
			 * processor save area.
			 */

			xtensa_coproc_savestate(&rtcb->xcp.cpstate);
#endif

			/* Restore the exception context of the rtcb at the (new) head
			 * of the ready-to-run task list.
			 */

			rtcb = this_task();

#if XCHAL_CP_NUM > 0
			/* Set up the co-processor state for the newly started thread. */

			xtensa_coproc_restorestate(&rtcb->xcp.cpstate);
#endif

#ifdef CONFIG_ARCH_ADDRENV
			/* Make sure that the address environment for the previously
			 * running task is closed down gracefully (data caches dump,
			 * MMU flushed) and set up the address environment for the new
			 * thread at the head of the ready-to-run list.
			 */

			(void)group_addrenv(rtcb);
#endif

#if CONFIG_RR_INTERVAL > 0
			rtcb->timeslice = MSEC2TICK(CONFIG_RR_INTERVAL);
#endif

			/* Then switch contexts */

			xtensa_context_restore(rtcb->xcp.regs);
		}
	}
}
